An apparatus for controlling functional elements of an internal combustion engine in order to achieve a target torque that is set based on an acceleration operating quantity by a driver and a requirement for a driving system or the like is known in the art (see, for example, Japanese Patent Laid-Open No. 2006-183506).
Also, an apparatus for controlling injection quantity in order to implement a required work load that is required by an acceleration operating quantity is known in the art (see, for example, Japanese Patent Laid-Open No. 2003-97330). The apparatus shown in this publication performs a subsidiary injection along with a main injection. More particularly, a work equivalent of the subsidiary injection is calculated in order to control the main injection so that the sum of the calculated work equivalent and a work equivalent of the main injection becomes equal to the above described work load.